Point‐Defect Engineering: Leveraging Imperfections in Graphitic Carbon Nitride (g‐C₃N₄) Photocatalysts toward Artificial Photosynthesis

Abstract

Graphitic carbon nitride (g‐C3N4) is a kind of ideal metal‐free photocatalysts for artificial photosynthesis. At present, pristine g‐C3N4 suffers from small specific surface area, poor light absorption at longer wavelengths, low charge migration rate, and a high recombination rate of photogenerated electron–hole pairs, which significantly limit its performance. Among a myriad of modification strategies, point‐defect engineering, namely tunable vacancies and dopant introduction, is capable of harnessing the superb structural, textural, optical, and electronic properties of g‐C3N4 to acquire an ameliorated photocatalytic activity. In view of the burgeoning development in this pacey field, a timely review on the state‐of‐the‐art advancement of point‐defect engineering of g‐C3N4 is of vital significance to advance the solar energy conversion. Particularly, insights into the intriguing roles of point defects, the synthesis, characterizations, and the systematic control of point defects, as well as the versatile application of defective g‐C3N4‐based nanomaterials toward photocatalytic water splitting, carbon dioxide reduction and nitrogen fixation will be presented in detail. Lastly, this review will conclude with a balanced perspective on the technical and scientific hindrances and future prospects. Overall, it is envisioned that this review will open a new frontier to uncover novel functionalities of defective g‐C3N4‐based nanostructures in energy catalysis.

A current overview of the oxidative desulfurization of fuels utilizing heat and solar light: from materials design to catalysis for clean energy

“…From an economic and environmental point of view, metal-free nanomaterials, like g-C 3 N 4 with its moderate band gap and considerable visible light absorption [240][241][242][243] and GO with its plentiful oxygen-containing groups and tunable electrical properties, 244 have been employed as emerging nanomaterials in photocatalysis. Besides supporting metallic nanomaterials, mesoporous g-C 3 N 4 was applied as the photocatalyst to desulfurize stimulated fuel in the presence of O 2 and visible light.…”

Lithium–Sulfur Battery Cathode Design: Tailoring Metal‐Based Nanostructures for Robust Polysulfide Adsorption and Catalytic Conversion

“…Among all types of metal-sulfur batteries, Li-S battery has been profiled to be the next-generation battery in the realm of energy storage to overcome the intermittent energy supply from renewable sources such as solar, wind, and tidal. [324] The cathode of Li-S batteries has been extensively researched over the past 5 years with an emphasis on nanostructured metal-based materials and their corresponding morphologies (Figure 26) to circumvent the issues encountered at the cathode such as polysulfide shuttling, insulating nature of sulfur, and large volume change of sulfur. To date, there are multipronged approaches to tackle these problems such as carbon-based nanomaterials and metal-based compounds with tunable shape and composition that serve to contain polysulfides as well as to achieve the complete reversible reduction of Li 2 S 2 to Li 2 S, which accounts for half the theoretical capacity.…”

Solvent Etching Process for Graphitic Carbon Nitride Photocatalysts Containing Platinum Cocatalyst: Effects of Water Hydrolysis on Photocatalytic Properties and Hydrogen Evolution Behaviors

“…Nevertheless, bulk g-C 3 N 4 prepared through direct polycondensation of nitrogen-rich precursors presents several obstacles that limit its practical applications: low specific surface area, fast recombination of photogenerated charge carriers, and its hydrophobic surface [ 12 , 13 , 14 ]. In the past decade, many researchers have made immense efforts to overcome these drawbacks, including heteroatom doping [ 15 ], heterostructure construction [ 16 , 17 , 18 ], defects engineering [ 19 , 20 , 21 , 22 , 23 ], and vacancy formation [ 24 ].…”